Gelled blasting oils and processes



United States Patent Oifice 3,542,611 GELLED BLASTING OILS AND PROCESSES John Leslie Fanala, Frank, Pa., assignor of twenty percent each to Glenn Edmundson, Elizabeth, William C. Lacy, Buena Vista, William A. Lewis, .Ir., Bunola, and Daniel J. Arico, Elizabeth, Pa. No Drawing. Filed Apr. 19, 1968. Ser. No. 722,546 Int. Cl. C06b 3/02 US. Cl. 149101 17 Claims ABSTRACT OF THE DISCLOSURE My disclosure includes a gel of an explosive material, said gel comprising a quantity of said explosive admixed with a quantity of gelatin.

The present invention relates to the safe handling of explosives, and more particularly to gelled or gellatinous explosives such as gelled nitroglycerin or nitroglycol and to methods for the preparation thereof.

Since the discovery of dynamite by Alfred Nobel, many attempts have been made to provide safe handling of explosives such as nitroglycerin (glycerol trinitrate), nitroglycol (ethylene glycol dinitrate) and other exceedingly dangerous nitro explosives. Previous efforts in this field have been directed to permanently diminishing the explosive power of these explosives. While the hazards entailed in transporting, handling and using these explosives have been reduced, their blasting power has been undesirably diminished and their use limited. For example in the blasting of oil wells, pure nitroglycerin is preferred 'over blasting gelatin or dynamite explosives.

It has long been recognized that pure nitroglycerin and nitroglycol in their liquid states have very valuable properties as an explosive. Their explosive properties however impose serious limitations in the transport and use of these explosives. When these explosives are gelled or colloidized in accordance with conventional practices, efforts are exerted to minimize the exudation of the normally liquid blasting oils from the matrix in which they are absorbed. Therefore, the explosives must be utilized for blasting purposes in the form in which it is shipped to the site of use. Frequently, the treated explosive is in solid form and therefore is difficult to load into the bore or other receptacle provided therefor. In other gelled or colloidized forms the treated explosive mixes readily with water which often is present in the bore. As a result the blasting power of the explosive is either considerably diminished, or the explosive fails to detonate.

An example of the conventional approach to handling explosives of the nitroglycerin class is described in the United States patent to Barab 1,371,215. Barab produces a gel by mixing propylene glycol and nitrocellulose. However, he reports that the gel is easily detonated although not as readily as pure nitroglycerin. The explosive is not easily recovered from the gel as little or no exudation is apparent. The Barab explosive evinces the usual compromise of lessened blasting effect and more difficult detonation to reduce somewhat the hazards of transporting and handling the explosive. Barab also discloses a dynamite or solid type explosive made by combining the aforedescribed gel or blasting gelatin with a quantity of sodiumnitrate, weed pulp and calcium carbonate. He reports, however, that the blasting power is only somewhat more powerful than conventional 40% dynamite made with nitroglycerin.

Nathan et al., 1,302,202 describes a similar process for gelatinizing and stabilizing mixtures of nitroglycerin and nitro cellulose. The gelatinizing and stabilizing agent or agents include certain ureas such as methyl phenyl urea,

3,542,611 Patented Nov. 24:, 1970 ethyl phenyl urea and methyl diphenyl urea. The explosive product however is relatively easily detonated and While of lessened blasting effect is still extremely hazardous in transporting and subsequent handling.

The United States patents to Barab 1,307,032; Hill 1,778,718; Bryan 1,879,064; Barnhart et al. 3,072,509 and Atkins 3,242,022 disclose similarly gelled and/or colloidized explosive which suffer from the same disadvantages.

Insofar as I am aware, all known forms of stabilized explosives, whether of the dynamite or blasting gelatin types employ an absorbant (dynamite) or an explosive (such as nitro cellulose) of lesser blasting effect to gelatinize or colloidize the explosive. In either case the blasting eifect of the explosive is diminished in varying degrees, and since dynamite or blasting gelatin types of explosives can readily be detonated in their transported forms, their transportation and subsequent handling is still extremely hazardous. Further, I am not aware of any dynamite or gelatin type explosive from which the primary explosive such as nitroglycerin or nitroglycol can be separated completely and quickly in the field for subsequent use in the pure form.

To reduce shipping and handling hazards of nitroglycerin, the most widely used commercial explosive, it is usually frozen to minimize the possibility of its detonation from shock forces. Unfortunately the freezing of nitroglycerin involves in itself considerable hazard as does proper thawing of the explosive at the site of its use. Although nitroglycerin is relatively stable in one of its frozen forms the temperature thereof must be carefully controlled in the area of about 13 C. If its frozen temperature drops for example to about 2 C. nitroglycerin assumes an extremely unstable crystalline form as is well known. As a result, the temperatures in this area maximize rather than reduce shipping and handling hazards. Moreover, the instability at low temperatures prohibits its use in cold weather. The stable form of nitroglycerin however leaves much to be desired as it still can be detonated without great difficulty. In consequence a considerable amount of complicated equipment is necessary to ship small quantities of the pure explosives.

In the case of nitroglycol the freezing point is sufiiciently low (-22.3 C.) as to preclude stabilization by freezing for purposes of transportation, without the use of prohibitively complicated equipment. Relatively little nitroglycol is used, therefore, in comparison to nitroglycerin because of the dangers involved in its transport and storage. Nitroglycol, however, is preferable to nitroglycerin for use in cold weather, where its low freezing point permits use in the pure liquid state. The vapors of both nitroglycerin and nitroglycol are exteremely poisonous, a hazard which is reduced in the case of nitroglycerin by freezing. The blasting force of nitroglycol is between 8 and 20% greater than that of nitroglycerin and therefore is a more efficient explosive. Widespread usage of nitroglycol in its pure form, however, awaits some means for stabilizing the explosive and for preventing exposure for transportation and handling of personnel to its extremely poisonous vapors.

I overcome these disadvantages of the prior art by providing explosives, such as gelled nitroglycerin or nitroglycol, which can be detnoated in the gelled state only with great difiiculty so that transportational and handling hazards are virtually eliminated. My novel gelling process can be effected with a minimum of hazard. Most importantly, my gelled explosives can be easily and quickly separated in pure form from the gelling agent. This can be accomplished without specialized equipment by relatively unskilled persons at the site of ultimate use. The explosives can be utilized in pure form with maximum blasting power.

In the case of the gelled nitroglycerin provided by my invention, the gelled explosive can be transported with much less hazard than frozen nitroglycerin as conventionally employed. The gelled nitroglycerin is not subject to destabilization at very low temperatures nor to significant volatilization. Gelled nitroglycol made in accordance with my invention exhibits similar advantages and both explosives when gelled, can be transported in concentrated form, i.e., in the neighborhood of 90% pure explosive. Shipment of pure explosive could be accomplished heretofore only at maximum hazard. Moreover, my invention obviates the necessity of shipping large quantities of clay, wood meal and other absorbants used to stabilize dynamite type explosives. Therefore, my invention permits non-hazardous transportation and handling of these exceedingly powerful explosives, without appreciably increasing the bulk thereof, while permitting their subsequent field usage in pure form. My invention, in the case of nitroglycol overcomes prior limitations upon its use in pure form imposed by its very low freezing point.

I accomplish these desirable results by providing a gel of an explosive material, said gel comprising a quantity of said explosive admixed with a quantity of gelatin.

I also desirably provide a similar explosive gel wherein said explosive is selected from the group consisting of nitroglycol and nitroglycerin.

I also desirably provide a method for gelling explosive materials, said process comprising the steps of preparing a solution of gelling agent, adding a quantity of explossive to said solution, thoroughly mixing said explosive and said solution, separating said explosive and the gelling agent admixed therewith from said mixture, and cooling said explosive and admixed gelling agent to form a gel.

I also desirably provide a method for handling explosive materials comprising the steps of gelling said material with a low temperature gelling agent, maintaining said gelled material at a relatively lower gelling temperature during transportation thereof, and Warming said gelled material to room temperature to separate pure explosive material from said agent for subsequent use.

In the following detailed descriptions of, my novel gelled explosive and of methods for gelling and degelling thereof, I cite two examples of appropriate explosives,

, viz., nitroglycerin and nitroglycol in exemplification of my invention, but not in limitation thereof. It will be understood, therefore, by those skilled in the art that my invention can be readily adapted for use with similar explosive materials, in the liquid, nitro-ester class.

EXAMPLE I Nitroglycol (glycol dinitrate) As a final step in the prepration of nitroglycol which is otherwise made in accordance with conventional processes the nitroglycol can be filtered through commercial grade sodium cloride or other suitable non-reactive dehydrating agent. While the filtering step facilitates gelling of the nitroglycol in accordance with my invention, it is not essential for the production of a gelatinous mixture of the nitroglycol in accordance with my method.

A quantity of practical grade gelatin is added to water and an aqueous solution is formed by heating the water. For example, about 0.6 gram of gelatin is dissolved in about 25 ml. of Water, and heated to a temperature of 80-90 C. to give a gelatin concentration of about 0.024 gram per ml.

.After the gelatin mixture has been completely dissolved the aqueous mixture is cooled to a room tempera ture or about 20 C.

A quantity of nitroglycol, in this example about two ml. is then added to about 8 ml. of the cooled gelatinous solution. Because of its greater density the nitroglycol will settle to the bottom of the aqueous gelatin solution.

However, the aqueous gelatin and nitroglycol layers are admixed by suitable stirring means until a uniform mixture of both materials appears in the container. When mixing is thus completed, the admixture is left to stand until a nitroglycol and gelatin admixture settles to the bottom as a cloudy, milky white, foamy bottom layer.

The mixture desirably is undisturbed for a period of 1-2 minutes (larger quantities will, of course, take longer periods for settling). When the foamed nitroglycol has completely settled the overlying layer of water and residual gelatin can be siphoned or decanted off.

The foamed nitroglycol is then refrigerated at a temperature of -6 C. to 20 C. to set the gel firmly. When the resulting emulsion (after mixing) is cooled to 6 C. a firm gel with a soft center was formed. However, the nitroglycol can be put into a firm gel throughout by cooling from 13 C. to -20 C. It should be noted, however, that firmness can also be increased by slight increases in the concentration of gelatin. The temperature of the gelled nitroglycol preferably is maintained about 15 C. or lower and desirably between 10 C. and 0 C. during shipment and subsequent handling of the material. Above 15 C. the gel becomes thin but still offers about 50-60% of the stabilization available at lower temperatures. Thus, my gelled explosive can be shipped Without the use of complicated refrigerating equipment by packing in ordinary ice. As discussed below, nitroglycol, when in its gelled state, as provided by my invention, can be detonated only with considerable difiiculty. The gelled material is not volatile and therefore does not emit the extremely poisonous fumes usually associated with nitroglycol and the like explosives.

In this example, ordinary gelatin is utilized, i.e., the soluble collagen conventionally obtained by boiling collagenous material such as bone, tendon, or cartilage in water. Among the many sources of gelatin, the composition is substantially invariable, beyond levels of purity. I have found that gelatin from any of the several available sources can 'be used in carrying out my invention although slight adjustments in the aforementioned concentrations may be necessary. In the specific examples set forth herein, I employed practical grade gelatin available from Fisher Scientific Co., Pittsburgh, Pa.

The term, gelatin, refers to a specific type of protein having the empirical formula G P X where:

G: glycine P=proline and hydroxyproline X=other amino acid A more specific composition (hydrolyzed) follows: (all figures are in grams per grams of protein) It has been found that nitroglycerin can be gelled in the same manner by using the method steps, gelling agent, proportions, and temperatures outlined above. Nitroglycerin gel likewise can be packed and shipped with ordinary ice.

I have found that nitroglycol and nitroglycerin can be gelled and regelled any number of times without damage to the explosive. After the nitroglycol gel or nitroglycerin gel has been shipped to the site of its ultimate use, nitroglycol or nitroglycerin in its pure state can be readily separated from the gelling agent by warming the gel to room temperature of about 20 C. When the explosive has thus been separated from the gelling agent, the original blasting power and sensitivity to detonation are completely restored. When the gelled material is warmed to room temperature the gelling agent (gelatin) collects on the top of the blasting oil and is readily decanted or siphoned off from the explosive.

When the nitroglycol or nitroglycerin has thus been freed from the gelling agent a Biuret test indicates the complete absence of any residual gelling agent in the freed explosive. As is well known, a Biuret test is'used to detect protein and is pertinent in this demonstration as gelatin is composed entirely of protein. A few drops of dilute copper sulphate solution and of nitroglycol freed from the gel provided by my invention are added to a saturated solution of sodium hydroxide. The results of the test is completely negative. Blank runs have been made with gelatin and previously ungelled nitroglycol. The gelatin run shows the usual purple color, while the nitroglycol run likewise gives negative results as expected.

As is known, nitroglycol and nitroglycerin in their pure liquid forms can be very easily detonated with small quantities of the usual detonator. Once gelled, however, in accordance with my invention, the gelled material can be detonated only' with great difiiculty, and the quantity of detonator is considerably increased. i

In practice, a very. small quantity (say /2 gram)- of mercury fulminate is requiredfor the detonationxof pure nitroglycol in its liquid state. When gelled in accordance with my invention, however, it is found that 5 grams of silver fulminate are required to detonate amere lO milliliters of the gel. Silver fulminate is several times more powerful than mercury fulminate and is outlawed in-this country for commercial use. Only 1 /2 grams of silver fulminate are required for example to detonate TNT (trinitrotoluene) in contrast to 7v grams of the commercially available mercury fulminate. As a further example of the stability of my gelled explosive, I was not able to detonate any quantity of the gelled explosive with a standard or commercially available No. 8 detonator. However, a No. 8 detonator will detonate powdered TNT but not cast TNT. Therefore, my gelled explosive should meet the ICC. requirements for a Class A (least sensitive) explosive.

The relative difliculty of detonating my novel gelled materials is even more surprising when one considers that the novel gelled explosives contain in the order of 90% of nitroglycerin or nitroglycol. When the pure explosive is desired, the gel is simply warmed to room temperature as mentioned previously with a recovery of very nearly 100% of the pure explosive. Even with relatively crude separation techniques in the field the loss of explosive is under 2%.

The mixture remains gelled and hence is stabilized at temperatures above the freezing point of water (at temperatures up to +10 C.) and therefore can be stored or shipped by the simple expedient of packing it in ice. When the explosive is recovered after shipment in this fashion there is no measurable loss of power even after storage for several weeks or longer in the gelled condition.

It is to be noted that my novel gelling process permits simpler handling techniques and eliminates complicated freezing and transporting equipment. Owing to its much greater stability the gelled mixture can be shipped in bulk form with little or no hazard. The gelling agent employed is readily available and is inexpensive in comparison to more commonly used stabilizers such as nitrocellulose. Moreover, the gel can be provided in semi-fluid but stabilized form to facilitate pumping during manufacturing or transportation. For example, I have found further that a soft gel is formed when the gelatin is reduced from .6 gram to .4 gram and the nitroglycol and gelatin mixture was cooled to -5 C. The stabilization of the last-mentioned soft gel is about 70% of that afforded by a firm gel. The semi-fluid gel thus formed can be more conveniently pumped to facilitate manufacturing and bulk transportation, if desired, but is likewise not readily detonated. Thicker explosive gels made in accordance with my invention can, however, be pumped by recently developed gel pumps.

Preparation of my novel gelled explosive is simple in comparison to conventional gelling processes. Since the gelatin solution and the explosives are both liquids, it is much easier and safer to achieve a homogeneous mixture than with the use of a liquid explosive phase and a solid stabilizer phase. Separation of the explosive is simplified by the differences in density of the immiscible liquid gelling agent and liquid explosive when the gelled explosive is warmed.

It will be readily understood therefore that my novel, gelled explosives are very stable when maintained at or below the stated temperature of +10 C., to maintain the gelled state. These explosives, then, can be readily transported and handled without the use of burdensome refrigerating equipment and without appreciable hazard. The ure explosive can be obtained only by warming the gel, as described above, and cannot be separated by freezing out. In the case of nitroglycerin, there is no danger of instability at its 2 C., labile state. Moreover, the process for gelling and degelling the explosives is not particularly hazardous. Most importantly, the explosives can be separated in pure form from their gels at the site of ultimate use without requirements of specialized equipment or highly trained personnel.

From the foregoing it will be apparent that novel and efiicient forms of gelled nitro explosive and process have been disclosed. While I have shown and described certain presently preferred embodiments of the invention and have illustrated presently preferred methods of practicing the same it is to be distinctly understood that the invention is not limited thereto but may be variously embodied and practiced within the scope of the following claims.

I claim:

1. A gel of an explosive material of the liquid nitroester class, said gel comprising a quantity of said explosive admixed with a quantity of gelatin, said gelatin having the empirical formula, G P X Where:

G=glycerine P=proline and hydroxyproline X=other amino acid 2. The combination according to claim 1 wherein said explosive is selected from the group consisting of nitroglycol and nitroglycerin.

3. The combination according to claim 2 wherein said explosive is nitroglycol.

4. The combination according to claim 2 wherein said explosive is nitroglycerin.

5. A method for gelling explosive materials of the liquid nitro-ester class, said process comprising the steps of preparing a solution of gelling agent, adding a quantity of explosive to said solution, thoroughly mixing said explosive and said solution, separating said explosive and the gelling agent admixed therewith from said mixture, and cooling said explosive and admixed gelling agent to form a gel, said gelling agent having the empirical formula, G P X where:

G=glycerine P=proline and hydroxyproline X=other amino acid 6. The method according to claim 5 including the steps of mixing said gelling agent with water, and decanting supernatant water and residual gelling agent from the explosive and admixed gelling agent.

7. The method according to claim 5 including the additional step of cooling the explosive and admixed gelling agent to a temperature between about C., to about 20 C.

8. The method according to claim wherein said explosive is first filtered through a non-reactive dehydrating agent.

9. The method according to claim 7 wherein the explosive and admixed gelling agent are cooled to a temperature in the range of C., to 20 C.

10. The method according to claim 9 wherein said gelatin is admixed with water in the ratio of about 0.4- 0.6 g. gelatin to about 25 ml. of water.

11. A method according to claim 6 including the additional steps of separating said geling agent from said explosive material to obtain substantially pure explosive material for subsequent use.

12. The method according to claim 5 including the additional steps of warming said gel] to separate substantially pure explosive material from said gell for subsequent use of said explosive material in substantially pure form.

13. A method for handling explosive materials selected from the group consisting of liquid nitro-esters comprising the steps of gelling said material with a low temperature gelling agent, maintaining said gelled material at a relatively lower gelling temperature to preserve the gelled condition thereof, and Warming said gelled material to room temperature separating substantially pure explosive material from said gelling agent for subsequent use of said explosive material in substantially pure form.

14. The method according to claim 13 wherein said gelling agent is gelatin.

15. The method according to claim 14 wherein said gelled material is maintained at a temperature of about 15 C., or lower during transportation thereof.

16. The method according to claim 10 wherein the gelatin-water admixture and a liquid explosive are admixed in the ratio of about 4:1 by volume.

17. The method according to claim 15 wherein said temperature is maintained between 0 C., and 10 C.

References Cited UNITED STATES PATENTS 1,999,828 4/1935 Wiggam l49-101 X 2,365,170 12/1944 Bitting et al 149101 X 2,413,946 1/1947 Bonotto 149-101 2,594,996 4/1952 Riley 149101 X 3,018,201 1/1962 Downard 149101 X BENJAMIN R. PADGETT, Primary Examiner S. J. LECHERT, JR., Assistant Examiner US. Cl. X.R. 14988, 109

' Y PO-ww UNITED STATES PATENT OFFICE (5/69) CERTIFICATE OF CORRECTION Patent No. 3,542,611 Dated November 24, 1970 Inventor(s) John Leslie Fanala It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, line 55 "prepration" should be read as --preparation--.

Claim 1, line 5 "glycerine" should be read as -glycine--.

Claim 5, line 10 "glycerine" should be read as --glycine--.

Claim 9, line 3, "10" should be read as --l3--.

Claim 11, line 1, "6" should be read as -5--; line 2, 'geling should be read as --gelling--.

Signed and sealed this 2nd day of May 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBE-IT GOT'ISCHALK Attesting Officer Co missioner of Patents 

